Investigation of the Hydrodynamic Condition Effects and Mass Transfer Rate on Enzymatic Hydrolysis of Mixed Microalgae

Microalgae with reserves of carbohydrates, high growth rate have been introduced as one of the most promising sources for bioethanol production. In this study, after culturing mixed microalgae species in photobioreactors, a nitrogen starvation strategy was used to increase the accumulation of carbohydrates in microalgae. Then, the sugars in the biomass were extracted using enzymatic hydrolysis by cellulase enzyme. For the first time, the enzymatic hydrolysis of microalgae is investigated by considering the dynamic conditions of the fluid inside the reactor. The results showed that increasing the system agitation more than the enzyme concentration affects the hydrolysis efficiency. At high speeds of 250 rpm, where the flow regime changes from slow to turbulent, the amount of sugar released is much higher than the values at low speeds of the stirrer. Also, adding baffle increases the mass transfer rate by preventing the formation of vortices and consequently increases the hydrolysis efficiency. But changingthe type of stirrer does not have a significant effect onthe hydrolysis process. Also in this study, the effect of agitation during the hydrolysis process was investigated by evaluating the mass transfer rate.